Its discovery suggests the world being explored by the NASA rover is more geologically advanced than is usually appreciated. The rover is now exploring parts of the Gale Crater in a spot known as the "clay-bearing unit", where it is using its drills to gather samples of the Martian soil where water once flowed. This area, positioned along the slope of Mount Sharp, as soon as featured lakes and streams, the remnants of which now seem within the type of clay mineral deposits. More recently, it took detailed images of "Strathdon", a rock made of dozens of sediment layers that have hardened into a brittle, wavy heap.

Scientists know that Mars was once a much wetter place than it is today, but whether all that moisture was supporting life on the Red Planet is still anyone's guess. Dubbed "Strathdon" by the Curiosity team, the brittle rock looks like a very big chunk of baklava, with its tiered, wavy rows. NASA speculates that the "wavy" nature of these layers hint at a "dynamic" environment, one that may have involved flowing water or wind (or a combination of both). "We're seeing an evolution in the ancient lake environment recorded in these rocks", says Fox. "It was not just a static lake. As a substitute of a linear process, the history of water was more complicated".

NASA's Curiosity rover, the machine that landed on Mars seven years ago, has sent back to Earth a series of images compiled into a bright high-resolution panorama.

A second photo (below) taken a day later with the rover's Mars Hand Lens Imager (MAHLI) - a camera affixed to Curiosity's robotic arm - showed the rock at a distance of 10 centimetres.

A few weeks earlier, while Curiosity was exploring a region within the clay-bearing unit, the rover stopped to take a 360-degree panorama as it stood next to a rocky outcrop named Teal Ridge.

NASA hopes the Curiosity rover, which "has a few more years before its nuclear power system degrades enough to significantly limit operations", can provide additional clues about the planet prior to the launch of the Mars 2020 rover mission.